var btns = document.getElementsByTagName("button");
var div1 = choose.getElementsByClassName("right");
var div2 = choose.getElementsByClassName("active");

for (var i = 0; i < div1.length; i++) {
    btns[i].onclick = function () {
        if(this.innerHTML=="+"){
            for(var i=0;i<div1.length;i++){
                div1[i].className="";
            }
        }
    }

}

